Method of making filter elements



Oct. 3, 1944.

METHOD Filed Oct. 18, 1941 qyiuae.

11v VENTOR A TTORNE Y5.

Patented Oct. I If.

I flaasarzs ME'rnon or MAKING rmren ELEMENTS ,Donat aoautiner,netm af vlch. i

Application October 18, 1941, Serial No. 415.352

7 Claims. .(ci. 210-9169) This invention relates to filters'andparticularly to filter packs, and has for its principal object theprovision of a construction that is easier and, therefore, moreeconomical to assemble and manufacture, and is of'improved appearance.

Objects-of the invention include the provisionof a filter pack having acentral opening and comprising a plurality of filtering members'orelements superposed alternately with intercalary members and forming aplurality of chambers, the intercalary members each comprising inner andouter members of annular or equivalent shape arranged in spaced relationwith respect the provision of a construction as above described in whichthe inner and outer annuli of each intercalary member are connectedtogether by one or'more radially extending webs or spokes; th provisionof a construction as above described in which the spaces between theinner and outer annuli of alternate intercalary members on each side ofsaid web are connected with the exterior of "the pack by breaks throughthe outer annuli; the provision of a construction as above described inwhich the spaces between the outer and-inner annuli-of alternateintercalary members on each side of the 'web thereof are connected withthe central opening by breaks through the inner annuli; the provision ofintercalary members of the type described that are of one-piececonstruction; and the provision of a filter pack of the type describedsecured together in a novel manner.

Other objects of the invention include the provision of a filter pack ofthe type described in which adjacent filtering and intercalary membersare integrally joinedtogether) the provision of a filter pack of. thetype described in which Further objects of the invention include, in-

,the manufacture of'a filter pack of th type described; the steps ofoperating upon a strip of material suitable for said filtering elementsor members and the intercalary members to form a stripcomprising-alternate filtering and inter-' calary members with each ofsaid members con;

'nected'to the next adjacent member'sby a pore tion integral with boththereof; and then folding said members in zig-zag relation intothedesired pack form; and the step in the manufacture or" a filter packof the type described from integrally joined filtering and intercalarymembers, of scorv ing the strip at th lines of junction between twoelements or membersalternately on opposite a sidesof the strip wherebyto provide a natural line of fold serving as a hinge between the'membersand facilitating the arrangement thereof in packs.

The above being among the objects of theQ present invention the sameconsists in'icertain 'novel features of construction, combinations ofparts, and step or steps of operation to behereinafter described withreference to the. accompanying drawing, and then claimed,'having theabove and otherobjects in view. In the accompanying drawing whichillustrates suitable embodiments of the present invention and in whichlike numerals refer'to li ke fparts throughoutthe'several difierentviews,

Fig. 1 is a partially' brokenvertical sectional view taken axiallythrough a filter embodyinga *filter pack constructed in accordancewiththe present invention;

Fig. 2 is an enlarged exploded view illustrating in perspective thevarious types of elements going to make up the filter pack employed inthe filters shown in Fig. 1; f a i Fig. 3 is a fragmentary plan view ofa form of blank applicable for use in forming a filter pack inaccordance with the present invention and in which the alternate filterand intercalary member areintegrally joined together;

Fig. .4 is an enlarged, fragmentary sectional view taken on the line 4-4of Fig. 3 and illustrating the preferred method of scoring the blank ofFig. 3; and,

Fig. 5 is a more or less diagrammatic view illustrating the manner offolding the blank ihownin Fig. 3 producing a filter pack thererom.

v The present inventionrelates to filter packs of the general typedisclosed and claimed in United States letters Patent No. 2,190,014,issued February 13, 1940, to Jacques COlas on Filter pack. In otherwords it comprises a filter packof, more or;less annular formationcomprising alternate filtering and: intercalary members placed one uponthe other to form the pack," the intercalary members spacing thefiltering members to form a. pocket or chamber between each adjacentpairof filtering members, 'and the intercalary members being alternatelyopen to operating filter members at their centers .;and the remainder ofwhich are oi the same outside diameter as the filtering members andspace the cooperating filtering members at their outer edges. It is tobe noted that intheconstruction of the above identified Colas patent thefiltering members between which the small intercalary.

members are interpositioned are in actual contact at their outer edgesand those filtering members between which the large intercalary mem bersare interpositioned are in contact with each otherat their centers.These intercalary members are broken in their circumference to formports to the pockets or chambers between their cooperating filteringmembers, those ports in the small annuli leading to the central bore ofthe, filter pack and those in the large annuli leading to the exteriorsurface of the filter pack. Inasmuch as the filtering members and theintercalary members are assembled by threading them on a pilot tube of asize to fit the. bore of the filtering members and of the small annuliintercalary members, it will be appreciated that the large annuliintercalary members being internally of much greater size than thediameter of the pilot tube must be lined by hand with the filteringmembers, and because of the inevitable misali nment bound to occur undersuch conditions in assembly the exterior surface of the finished pack isinevitably rough and unfinished in appearance. Furthermore, because oi.the fact that alternate filter members actually contact each other attheir inner and outer edges, which contact inevitably extends radiallyoutwardly and radially inwardly, respectively, to a greater distancethan the radial dimensions of the corresponding intercalary members, theeffective area of the filtering members is unnecessarily restricted andis open to being unnecessarily plugged by the building up of filter cakethereon.

The present invention has for its principal object a constructionovercoming the above discussed disadvantages of the construction shownand described in the above identified Colas patent. This is accomplishedby forming each intercalary member both with an inner and outer annulusthus spacing the cooperating filtering members by the full thickness ofthe intercalarymember for the full distance between the inner and outerannuli. Moreover the construction is such as to permanently connect theinner and outer annuli of each intercalary member together, as by aninterconnecting web or spoke, which preferably is integral with both.The inner annuli of each intercalary member having an inner diametersuch as to be relatively closely received by the pilot tube, itautomatically acts to center the outer annulus of each intercalarymember with the cooperating filtering members. This web or spoke ispreferably extended radially between the annuli of each intercalarymember and preferably the web extends in two or more directions radiallyoutwardly from the inner annulus to the outer annulus. As a result ofthis construction the concentricity of the inner and outer annulus ofeach intercalary member is assured as well a the concentricity of theouter annulus with the cooperating filtering members in following outthe normal method of assembly upon a pilot tube. It, therefore,eliminates any requirement of skill in the workman performing theassembly and results in a filter pack having a small exterior surface.Moreover, by completely spacing the filtering members between the innerand outer annuli. except over the area of the webs or spokes which inthemselves serve, as supports between the inner outer'annuli and aid in:preventing'contact of the filtering members between the annuli throughsagging, the effectiveness of the filtering members is increased acompared to the construction of the Colas patent.

. Referring now to the accompanying drawing, a. complete filterincluding a pack constructed in accordance with the present invention isillustrated in Fig. 1. In this connection it will be appreciated thatthe particular construction of the housing in which the pack is locatedand the manner of'supporting the pack therein may be varied to suit thedesires of the particular designer or manufacturer and may varyaccording to the condition of use. and liquid to be filtered, theparticular construction shown for the purpose of enclosing andsupporting the filter pack being merely by way of illustration. In Fig.1 the filter packfis indicated generally at" and is shown'as beingenclosed in a cup-shaped housing I! having a bottom wall I4 and an openupper. end. It will, of course, be appreciated that in use the liquidmay be passed through the pack from the center outwardly or from theoutside to the center, the latter condition being assumed for thepurpose of explanation. The top of the housing I2 is closed by a coverplate It having an inlet passage l3 therethrough in the outer end 01'which a pipe or tube "20. is threaded for conveying the liquid to befiltered thereto. The cover II is provided with an outlet passage 22 inthe outer end of which a pipe or tube 24 is threaded and which serves toconvey the filtered liquid away from the filter. The cover I6 is sealedto the housing H by nfeans of a gasket 28 received in an annular groove23 formed in the lower face of the cover I6 in concentric relation withrespect to the walls of the housing i2.

The filter pack III is provided with a central bore therethrough inwhich a tube 30, provided with a multiplicity oi. perforations 32 overthat length thereof confined within the pack III, is relatively looselyreceived so as to form an annular passage between it and the bore of thefilter pack. The upper end of the tube 30 is threaded into the lower endof the bore 22 in the cover l3. Below the filter pack l0 the tube 30 isprovided with an outwardly directed flange 3i fixed thereto betweenwhich and the bottom end of the filter' pack 10 is positioned a gasket36 surrounding the tube. A similar gasket 38 is positioned between theupper end of the filter pack III in surrounding relation with respect tothe upper end of the tube 30. The gaskets 36 and 38 are each relativelyclosely but slidably received on the tube 30 and each has an extendedneck portion of reduced diameter which fits in the more of the filterpack to thereby center it on'the tube 30. Thus the filter pack ill whenpositioned on the tube 30 is supported from the cover I 6 and iscompressed to a greater or lesser extent axially thereof by threadingthe tube 30 upwardly into the cover l6 thereby to compress the gaskets38 and 38 against the opposite ends of the pack to seal the ends oi thepack ill to the opposite ends of the tube 30. The bottom wall ll of thehousing I2 is provided with an opening 40 therein through which a bolt42 is projected upwardly and threaded into the bore of the tube 30, thehead of the bolt bearing acts through the tube 30 to pull the cover ldownwardly into sealing relation with respect to .the housing l2. Thusthe tube 31! not only serves the'function of an oil passage forconducting the filtered fluid out of the filter but also as a means foraiding in the securing of the cover l5 to the housing 12.

The filter pack III which comprises the subject matterpf the presentinvention and except for the two opposite end members 45 which are preferably made up from relatively heavy and/or rigid material adapted totake the compressive strains applied thereto when clamping the pack H)in place in the filter, is made up of alternate filtering elementsor'members 50 and intercalary members indicated generally at 52. Whileit will be appreciated that the pack I!) may be of any suitablecross-sectional configuration, as for instance square, octagonal, round,or the like, it is preferably made of the latter shape and is soillustrated in the drawing, reference made hereinafter to such shapebeing descriptive of the particular shape shown in the drawing but notlimiting the invention to a filter pack or members or elements thereforof circular conformation.

The filter members 50, which are best brought out in Fig. 2, are in theparticular case shown of disc-like character each having a centralopening 54 for the purpose of receiving the tube 30. The intercalarymembers 52 each comprise an inner annulus 55 and an outer annulus 58 andin accordance with the present invention these two annuli are connectedtogether by means of one or more webs orspokes 50. Preferably the webs5|] are formed integrally with the annuli 55 and 58 as indicated so thateach intercalary member 52 may be stamped in one piece out of a singlesheet of material. The annuli 55 and 58 are arranged concentrically witheach other and in radially spaced relation which relation is maintainedby the webs 50. While one or more webs may be employed in the broaderaspects of the present invention, two webs arranged diametrically ofeach intercalary member as shown are preferably employed. The internaldiameter of the inner annulus of each intercalary member 52 is of thesame size as the openings 54 in the filter members 50 and is concentrictherewith in the completed pack. The outer annulus 58 of eachintercalary member 52 is preferably of. an outer diameter equal to theouter diameter of the filter discs 50.

It will be appreciated that by interposing an intercalary member 52between each pair of filter members 50, the filter members 50 are spacedfrom each other by the thickness of the intercalary members 52 and inthe particular construction shown a pair of chambers or pockets, one oneach side of the webs 50, are thus provided between each pair of filtermembers 50.

Alternate intercalary members 52 have portions of their outer annulus 58broken away as at 52 to provide passages or ports from the exterior ofthe filter pack to the pockets thus formed therein between thecooperating filter members 50. The remaining intercalary members 52having their inner annulus 55 broken away as at 54 to provide passagesor ports from each of the associated pockets to the bore of the pack l0and, therefore, to the perforated tube 35. Thus liquid under pressureintroduced into the casing I! may find its way through the ports 52inaltemate intercalary members '52 to the space betweenaltemate pairs offilteringmembers 50 and, after passing axially throughsuch filteringmembers into the space between such filtering members and their nextadjacent filtering members, may flow through the ports 54 into the spacearound the tube 30 and thence through the openings 32 therein to theinterior of the tube and be discharged from the filter through thepassage. It will be appreciated that the filter pack thus provides alarge area of filtering surface for its size as such filtering area isequivalent to the combined areas of the discs 50 less that portionthereof overlain by the intercalary members 52.

The webs or spokes 60 of alternate intercalary members 52 arepreferably, but not necessarily, angularly spaced from each other by' 90degrees. This is so the webs or spokes 50 of those intercalary members52 having the ports 54 will support and space the cooperating filterdiscs 50 in line with the ports 52 of the remaining intercalary membersand, likewise, the webs or spokes of these remaining intercalary memberswill support the cooperating filter discs 50 in line with the ports 54of the first mentioned intercalary members. This feature, therefore,aids in preventing the collapse of two adjacent filter discs in linewith the ports 52 or 64 for the space betweenthem. Another advantage ofthis arrangement is that the ports 52 and 54 of alternate intercalarymembers are angularly spaced from each other by 90 degrees and this aidsin preventing the building of filter cake at the entrance ports.

The intercalary members 52 serving no filtering function themselves may,of course, be made of anysuitable material capable of properly spacingthe filter members 50 and unaffected by the liquid to be filtered. Theymay, of course, be made up of one thickness or several thicknesses ofmaterial. Likewise they may be of the same thickness as the filteringdiscs 50 or they may be of greater or lesser thickness. They may be madefrom metallic or non-metallic material as desired. It will be preferablein most cases, however, if the intercalary members 52 are made from thesame material as the filtering discs 50 as this simplifies the stock ofmaterials required to be kept on hand in the manufacture of the filterpacks.

The filtering discs 50 may be made up of one or more thicknesses ofsuitable material capable of meeting the problem involved in anyparticular case. In other words the porosity of the material willordinarily vary according to the size of the particles required to befiltered out thereby and, of course, such material must 'not be affectedadversely by the materials to be filtered thereby. In the broaderaspects of the invention the material from which the discs 50 are formedmay be leather, fabric, or other suitable fibrous materials, Preferablybut not necessarily in all cases such material should have sufilcientinherent rigidity to maintain the pockets in the intercalary members. Ihave found that where petroleum products are to be filtered, such asgasoline, fuel oil, or lubricating oil, the filter discs 50 may beformed from suitable grades of paper or paper stock. Preferably wheresuch paper or paper stock is employed it should be of a type notmaterially affected by the small amounts of water that occasionally findtheir way into petroleum products.

Paper made from Halfa or Esparto stock, or the equivalent,isparticul-arly adaptable for use in this connection as it is of aporous nature, can be produced in varying porosities, is not affected bypetroleum products and is resistant to the action of water in thequantities usually found in petroleum products. When such type of paperis employed in a single thickness, it is preferably employed inthicknesses ranging from forty thousandths of an inch to eightythousandths of an inch when employed for filtering the lubricating oilof an internal combustion engine, for instance. Other grades and typesof paper may, of course, be employed when capable of meeting theconditions above set forth and, of course, the thickness thereof mayvary to a greater or lesser extent from the thicknesses above givendepending upon the particular characteristics of such other paper,depending upon the particular material to be filtered thereby, and alsodepending upon the pressures or other conditions met with in operation.

In assembling the filter pack ill in accordance with the presentinvention a dummy tube or pilot rod is used. This dummy tube or pilotrod is of a diameter to be relatively closely but slidably received inthe central openings 54 of the filter discs 50 and the inner amiuli'56of the intercalary members 52. In such case one of the end members 46 isfirst applied to the tube, it is then followed by one of the intercalarymembers 52, for instance, as a matter of illustration; one of suchintercalary members having the ports 62 in the outer annulus 58 thereof,then followed by a filter disc or member 50, then followed by anotherintercalary member 52 but this time one of which has ports 64 in theinner annulus 56 thereof, this being followed by another filtering disc50, and this sequence of parts applied to the tube repeated until thedesired axial length of the filter pack has been reached, after whichthe opposite end member 46 is applied,

The pack thus assembled is then preferably compressed axially to aslight extent and is then secured together as a unit. This latter may beaccomplished by suitable binding tapes extending axially of the packfrom one end member 46 to the opposite end thereof as, for instance, asillus trated in the Colas patent above identified, but preferably and inaccordance with a further phase of the present invention I prefer toapply a coating of material to the exterior surface of the filter packwhich when dry will serve to maintain the various members or elements ofthe pack in assembled relation and at the same time will impart a morefinished appearance to it. Such material may be applied in the samemanner as any other coating, that is by brush, spraying or the like.Where the filter is to be employed for filtering petroleum products itmay consist Of shellac, suitable artificial enamels such as now aregenerally found upon the market, or other suitable or equivalentmaterial. While such material itself is impervious to the passage of theliquid to be filtered therethrough, nevertheless the ports 62 inalternate intercalary members 52 will permit the passage of the liquidto the spaces or pockets between the filtering discs 50- and thus haveno adverse effect on the efficiency of the filter pack.

In Figs. 3, 4 and 5 a modified method of forming a filter pack such as iis illustrated and this constitutes a further phase of the presentinvention. The parts shown in Figs. 3, 4 and 5 are indicated by the samenumerals as are employed in Figs. 1 and 2 except that such numerals beara prime mark. Consequently it is not necessary to go into full detailwith respect to the construction of each of the various elements butsimply to point out the differences existing in the two constructions.As illustrated in Figs. 3, 4 and 5 a plurality of the members 50 and52.are formed from a single sheet or strip of.material and in stampingthem out or otherwise forming them they are not completely severed fromeach other but instead each member is connected to its adjacent memberover a short length of the material between them, for instance asillustrated at a in Fig. 3. The centers of the members 50 and 52 arepreferably located in line with each other as shown. In forming up thestrip illustrated in Fig. 3 the members 50, of course, alternate withthe members 52 and alternate members 52 are, of course, alternatelybroken or ported as at 64' through their central annulus 56 and throughtheir outer annulus 58 as at 52', respectively. The line of connection abetween alternate members 50' and 52' are preferably scored, asindicated at 10 in Fig. 4, in a direction perpendicular to the lineconnecting the centers of the various members and preferably, asillustrated in Fig. 4, alternately on opposite sides of the strip formby such members. In this manner the lines 0 connection a serve'asalternately ioldable hinges connecting these members so that they may bereadily folded accordionwise as illustrated in Fig. 5 to bring them intothe same stacked relation, as the'equivalent members in Fig. 1. Insteadof the scoring, but preferably in addition thereto, the material may bepierced or perforated as indicated at a plurality of closely adjacentpoints over each line of connection a so as to further weaken thematerial along such line to further assure the bending of the materialalong such line in the folding operation. While it may, of course, bepreferable that the length of the strip illustrated in Fig. 3 besufficiently long to include all of the elements required for onecomplete filter pack such as the pack it illustrated'in Fig. 1, this is,of course, not necessary in all cases as a sufficient number of shorterstrips may be folded up and applied together to obtain a filter pack ofthe desired axial length, i

It will, of course, be appreciated that the construction illustrated inFigs. 3, 4 and 5 eliminates the construction illustrated in Fig. 2, thespokes 50 in alternate members 52' being automatically located incrossed relation with respect to each other and being so located in theoriginal strip, thus requiring no care on the part of the operator to soposition them in assembly of the pack. It also eliminates the need ofemploying the dummy or pilot rod'in assembling the pack. While in thecompleted pack the adjacent members 50 and 52- will be connectedtogether, and throughout the entire filter pack when made up from asingle strip such as illustrated in Fig. 3, this is an advantage ratherthan a disadvantage inasmuch as it aids the adhesive coating applied tothe final product in holding the pack in assembled relationship. Thematerial from which the elements or members 50' and 52 in Fig. 3 areconstructed from may, of course, be the same or equivalent to thematerial from which the elements 50 and 52 previously described areconstructed from.

Having thus described my invention what I claim by Letters Patent is:'

1. In the manufacture of a filter pack-formed from alternate filteringmembers of one formation and intercalary members of a differentformation arranged in stacked relation, the steps of cutting a strip offiltering material of uniform width to form a strip comprising saidfiltering members each having a central tube receiv ing aperture andsaid intercalary members each comprising a frame-like structure inalternating relationship and integrally connected to one another along aline of limited length, then folding said strip of alternating filteringand intercalary members on said lines in accordion-like relationship tobring them into face to face and contacting relationship, and securingthem in such relationship.

2. In the manufacture of a filter pack formed from alternate filteringmembers of one formation and intercalary members of a differentformation arranged in stacked relation, the steps of cutting a strip offiltering material of uniform width to form a strip comprising saidfiltering members each having a central tube receiving aperture and saidintercalary members each comprising a frame-like structure inalternating relationship and integrally connected to one another along aline of limited length, scoring said strip along said lines alternatelyon opposite sides of said strip over the length thereof, folding saidstrip on said lines alternately in opposite directions to bring saidmembers into face to face and contacting relationship, and then securingsaid members against separation.

3. The method of forming a filter pack of the annular type consisting ofcentrally apertured filtering members and alternate intercalary memberswherein the intercalary members consist of inner and outer annuliconnected together by a pair of diametrically arranged spokes, the stepsof operating upon a strip of filtering material to alternately form saidfiltering members and said intercalary members each connected to thenext by an unsevered portion of said material, with the spokes inalternate intercalary members in transverse relation with respect to theremaining intercalary members, and with breaks in the inner annuli ofalternate intercalary members and in the outer annuli of the remainingof said intercalary members, then folding said strips about theunsevered lines of connections between said members accordionwisewhereby to bring said members into face to face and contactingrelationwith respect to each other, and securing said members together.

4. In the manufacture of a filter pack formed from alternate filteringmembers of one formation and intercalary members of a differentformation arranged in stacked relation, the steps of cutting a strip offiltering material of uniform width to form a strip comprising saidfiltering members each having a central tube receiving aperture and saidintercalary members each comprising a frame-like structure inalternating relationship and integrally connected to one another along aline of limited length, perforating said strip on said lines, foldingsaid strip on said lines alternately in opposite directions to bringsaid members into face to face and contacting relationship, and thensecuring said members against separation.

5. In the manufacture of a filter pack formed from alternate filteringmembers of one formation and intencalary members of a differentformation arranged in stacked relation, the steps of cutting a strip offiltering material of uniform width to form a strip comprising saidfiltering members each having a central tube receiving aperture and saidintercalary members each comprising a frame-like structure inalternating relationship and integrally connected to one another along aline of limited length, scoring said strip along said lines alternatelyon opposite sides of said strip over the length thereof, perforatingsaid strip on said lines, folding said strip on said lines alternatelyin opposite directions to bring said members into face to face andcontacting relationship, and then securing said members againstseparation.

6. In the manufacture of a filter pack comprising a stack consisting ofa plurality of filter members and a plurality of intercalary members ofsubstantially the same external contour, with the filter membersseparated from each other by intercalary members, and with each of saidmembers arranged in fiat contacting relationship with respect to thenext adjacent members,

the steps of cutting a strip of filtering material to form a one-piecestrip comprising a plurality of said filler members each of sheet likeform with a central tube receiving aperture and a plurality of saidintercalary members each of frame-like structure with the major portionof its central area removed with each of said filter members bounded ateach edge thereof in the length of the strip by an intercalary memberintegrally connected thereto, scoring the line of connection betweensaid members with the score between each member and the member nextadjacent thereto on one side thereof on one side of said strip and withthe score between it and the other member next adjacent thereto on theother side of said strip, then folding said members accordionwise onsaid lines of fold to bring each member into aligned and fiat contactingrelationship with the members next adjacent thereto to form a stack, andthen permanently securing all of said members in said stack together.

7. In the manufacture of a filter pack comprising a stack consisting ofa plurality of filter members and a plurality of intercalary members ofsubstantially the same external contour arranged in fiat contactingrelationship and with each adjacent pair of filter members separated byat least one intercalary member, the steps of cutting a strip offiltering material to form a one-piece strip comprising a line of saidfilter members each of sheet-like form having a single central tubereceiving aperture each of which is separated from the next adjacentfilter member by at least one intercalary member each comprising arelatively narrow perimetri-cally extending band and with said filtermembers and said intercalary members in said strip integraiiy connectedtogether by a line of fold extending transversely of the length of saidstrip, then folding said trip accordionwise on said lines of fold tobring each of said members into fiat contacting and aligned relationshipwith respect to the next adjacent members connected thereto in saidstrip to form a stack, and then permanently securing all of said memberstogether in said stacked relation.

DONAT A. GAUTHIER.

